Added Deletion to Bulletin Board Server and Local Client

bulletin-board-client/src/main/java/meerkat/bulletinboard/CachedBulletinBoardClient.java

@@ -1,168 +1,338 @@
 package meerkat.bulletinboard;
 
 import com.google.common.util.concurrent.FutureCallback;
-import com.google.common.util.concurrent.ListeningScheduledExecutorService;
-import com.google.common.util.concurrent.MoreExecutors;
 import com.google.protobuf.ByteString;
 import meerkat.comm.CommunicationException;
-import meerkat.protobuf.BulletinBoardAPI;
 import meerkat.protobuf.BulletinBoardAPI.*;
 import meerkat.protobuf.Voting.*;
 
-import java.util.ArrayList;
-import java.util.Collection;
 import java.util.List;
-import java.util.concurrent.Executors;
 
 /**
  * Created by Arbel Deutsch Peled on 03-Mar-16.
  * This is a full-fledged implementation of a Bulletin Board Client
  * It provides asynchronous access to several remote servers, as well as a local cache
- * Read/write operations are performed on the local server
+ * Read operations are performed on the local server
+ * Batch reads are performed on the local server and, if they fail, also on the remote servers
+ * Write operations are performed first on the local server and then on the remotes
  * After any read is carried out, a subscription is made for the specific query to make sure the local DB will be updated
  * The database also employs a synchronizer which makes sure local data is sent to the remote servers
  */
-public class CachedBulletinBoardClient implements SubscriptionAsyncBulletinBoardClient {
+public class CachedBulletinBoardClient implements SubscriptionBulletinBoardClient {
 
-    private final BulletinBoardClient localClient;
+    private final AsyncBulletinBoardClient localClient;
     private AsyncBulletinBoardClient remoteClient;
     private BulletinBoardSubscriber subscriber;
 
-    private final int threadPoolSize;
+    private class SubscriptionStoreCallback implements FutureCallback<List<BulletinBoardMessage>>  {
-    private final long failDelayInMilliseconds;
-    private final long subscriptionIntervalInMilliseconds;
 
-    public CachedBulletinBoardClient(BulletinBoardClient localClient,
+        private final FutureCallback<?> callback;
-                                     int threadPoolSize,
+
-                                     long failDelayInMilliseconds,
+        public SubscriptionStoreCallback(){
-                                     long subscriptionIntervalInMilliseconds)
+            callback = null;
-            throws IllegalAccessException, InstantiationException {
+        }
+
+        public SubscriptionStoreCallback(FutureCallback<?> callback){
+            this.callback = callback;
+        }
+
+        @Override
+        public void onSuccess(List<BulletinBoardMessage> result) {
+            for (BulletinBoardMessage msg : result) {
+                try {
+                    localClient.postMessage(msg);
+                } catch (CommunicationException ignored) {
+                    // TODO: log
+                }
+            }
+        }
+
+        @Override
+        public void onFailure(Throwable t) {
+            if (callback != null) {
+                callback.onFailure(t);  // This is some hard error that cannot be dealt with
+            }
+        }
+
+    }
+
+    /**
+     * Creates a Cached Client
+     * Assumes all parameters are initialized
+     * @param localClient is a Client for the local instance
+     * @param remoteClient is a Client for the remote instance(s); Should have endless retries for post operations
+     * @param subscriber is a subscription service to the remote instance(s)
+     */
+    public CachedBulletinBoardClient(AsyncBulletinBoardClient localClient,
+                                     AsyncBulletinBoardClient remoteClient,
+                                     BulletinBoardSubscriber subscriber) {
 
         this.localClient = localClient;
-        this.threadPoolSize = threadPoolSize;
+        this.remoteClient = remoteClient;
-        this.failDelayInMilliseconds = failDelayInMilliseconds;
+        this.subscriber = subscriber;
-        this.subscriptionIntervalInMilliseconds = subscriptionIntervalInMilliseconds;
-
-        remoteClient = new ThreadedBulletinBoardClient();
 
     }
 
     @Override
-    public MessageID postMessage(BulletinBoardMessage msg, FutureCallback<Boolean> callback) {
+    public MessageID postMessage(final BulletinBoardMessage msg, final FutureCallback<Boolean> callback) {
-        return null;
-    }
 
-    @Override
+        return localClient.postMessage(msg, new FutureCallback<Boolean>() {
-    public MessageID postBatch(CompleteBatch completeBatch, FutureCallback<Boolean> callback) {
+            @Override
-        return null;
+            public void onSuccess(Boolean result) {
-    }
+                remoteClient.postMessage(msg, callback);
+            }
 
-    @Override
+            @Override
-    public void beginBatch(BeginBatchMessage beginBatchMessage, FutureCallback<Boolean> callback) {
+            public void onFailure(Throwable t) {
+                callback.onFailure(t);
+            }
+        });
 
     }
 
     @Override
-    public void postBatchData(byte[] signerId, int batchId, List<BatchData> batchDataList, int startPosition, FutureCallback<Boolean> callback) {
+    public MessageID postBatch(final CompleteBatch completeBatch, final FutureCallback<Boolean> callback) {
+
+        return localClient.postBatch(completeBatch, new FutureCallback<Boolean>() {
+            @Override
+            public void onSuccess(Boolean result) {
+                remoteClient.postBatch(completeBatch, callback);
+            }
+
+            @Override
+            public void onFailure(Throwable t) {
+                callback.onFailure(t);
+            }
+        });
 
     }
 
     @Override
-    public void postBatchData(byte[] signerId, int batchId, List<BatchData> batchDataList, FutureCallback<Boolean> callback) {
+    public void beginBatch(final BeginBatchMessage beginBatchMessage, final FutureCallback<Boolean> callback) {
+
+        localClient.beginBatch(beginBatchMessage, new FutureCallback<Boolean>() {
+            @Override
+            public void onSuccess(Boolean result) {
+                remoteClient.beginBatch(beginBatchMessage, callback);
+            }
+
+            @Override
+            public void onFailure(Throwable t) {
+                callback.onFailure(t);
+            }
+        });
 
     }
 
     @Override
-    public void postBatchData(ByteString signerId, int batchId, List<BatchData> batchDataList, int startPosition, FutureCallback<Boolean> callback) {
+    public void postBatchData(final byte[] signerId, final int batchId, final List<BatchData> batchDataList,
+                              final int startPosition, final FutureCallback<Boolean> callback) {
+
+        localClient.postBatchData(signerId, batchId, batchDataList, startPosition, new FutureCallback<Boolean>() {
+            @Override
+            public void onSuccess(Boolean result) {
+                remoteClient.postBatchData(signerId, batchId, batchDataList, startPosition, callback);
+            }
+
+            @Override
+            public void onFailure(Throwable t) {
+                callback.onFailure(t);
+            }
+        });
 
     }
 
     @Override
-    public void postBatchData(ByteString signerId, int batchId, List<BatchData> batchDataList, FutureCallback<Boolean> callback) {
+    public void postBatchData(final byte[] signerId, final int batchId, final List<BatchData> batchDataList, final FutureCallback<Boolean> callback) {
+
+        localClient.postBatchData(signerId, batchId, batchDataList, new FutureCallback<Boolean>() {
+            @Override
+            public void onSuccess(Boolean result) {
+                remoteClient.postBatchData(signerId, batchId, batchDataList, callback);
+            }
+
+            @Override
+            public void onFailure(Throwable t) {
+                callback.onFailure(t);
+            }
+        });
 
     }
 
     @Override
-    public void closeBatch(CloseBatchMessage closeBatchMessage, FutureCallback<Boolean> callback) {
+    public void postBatchData(final ByteString signerId, final int batchId, final List<BatchData> batchDataList,
+                              final int startPosition, final FutureCallback<Boolean> callback) {
+
+        localClient.postBatchData(signerId, batchId, batchDataList, startPosition, new FutureCallback<Boolean>() {
+            @Override
+            public void onSuccess(Boolean result) {
+                remoteClient.postBatchData(signerId, batchId, batchDataList, startPosition, callback);
+            }
+
+            @Override
+            public void onFailure(Throwable t) {
+                callback.onFailure(t);
+            }
+        });
+
+    }
+
+    @Override
+    public void postBatchData(final ByteString signerId, final int batchId, final List<BatchData> batchDataList, final FutureCallback<Boolean> callback) {
+
+        localClient.postBatchData(signerId, batchId, batchDataList, new FutureCallback<Boolean>() {
+            @Override
+            public void onSuccess(Boolean result) {
+                remoteClient.postBatchData(signerId, batchId, batchDataList, callback);
+            }
+
+            @Override
+            public void onFailure(Throwable t) {
+                callback.onFailure(t);
+            }
+        });
+
+    }
+
+    @Override
+    public void closeBatch(final CloseBatchMessage closeBatchMessage, final FutureCallback<Boolean> callback) {
+
+        localClient.closeBatch(closeBatchMessage, new FutureCallback<Boolean>() {
+            @Override
+            public void onSuccess(Boolean result) {
+                remoteClient.closeBatch(closeBatchMessage, callback);
+            }
+
+            @Override
+            public void onFailure(Throwable t) {
+                callback.onFailure(t);
+            }
+        });
 
     }
 
     @Override
     public void getRedundancy(MessageID id, FutureCallback<Float> callback) {
 
-    }
+        remoteClient.getRedundancy(id, callback);
-
-    @Override
-    public void readMessages(MessageFilterList filterList, FutureCallback<List<BulletinBoardMessage>> callback) {
 
     }
 
     @Override
-    public void readBatch(BatchSpecificationMessage batchSpecificationMessage, FutureCallback<CompleteBatch> callback) {
+    public void readMessages(MessageFilterList filterList, final FutureCallback<List<BulletinBoardMessage>> callback) {
+
+        localClient.readMessages(filterList, callback);
+
+        subscriber.subscribe(filterList, new SubscriptionStoreCallback(callback));
+
+    }
+
+    @Override
+    public void readBatch(final BatchSpecificationMessage batchSpecificationMessage, final FutureCallback<CompleteBatch> callback) {
+
+        localClient.readBatch(batchSpecificationMessage, new FutureCallback<CompleteBatch>() {
+            @Override
+            public void onSuccess(CompleteBatch result) {
+                callback.onSuccess(result);     // Read from local client was successful
+            }
+
+            @Override
+            public void onFailure(Throwable t) {
+
+                // Read from local unsuccessful: try to read from remote
+
+                remoteClient.readBatch(batchSpecificationMessage, new FutureCallback<CompleteBatch>() {
+
+                    @Override
+                    public void onSuccess(CompleteBatch result) {
+
+                        // Read from remote was successful: store in local and return result
+
+                        localClient.postBatch(result, new FutureCallback<Boolean>() {
+                            @Override
+                            public void onSuccess(Boolean result) {}
+                            @Override
+                            public void onFailure(Throwable t) {}
+                        });
+
+                        callback.onSuccess(result);
+
+                    }
+
+                    @Override
+                    public void onFailure(Throwable t) {
+
+                        // Read from remote was unsuccessful: report error
+                        callback.onFailure(t);
+
+                    }
+
+                });
+
+            }
+
+        });
 
     }
 
     @Override
     public void querySync(SyncQuery syncQuery, FutureCallback<SyncQueryResponse> callback) {
 
+        localClient.querySync(syncQuery, callback);
+
     }
 
     @Override
-    public void init(BulletinBoardClientParams clientParams) {
+    /**
-
+     * This is a stub method
-        remoteClient.init(clientParams);
+     * All resources are assumed to be initialized
-
+     */
-        ListeningScheduledExecutorService executorService = MoreExecutors.listeningDecorator(Executors.newScheduledThreadPool(threadPoolSize));
+    public void init(BulletinBoardClientParams clientParams) {}
-
-        List<SubscriptionAsyncBulletinBoardClient> subscriberClients = new ArrayList<>(clientParams.getBulletinBoardAddressCount());
-
-        for (String address : clientParams.getBulletinBoardAddressList()){
-
-            SubscriptionAsyncBulletinBoardClient newClient =
-                    new SingleServerBulletinBoardClient(executorService, failDelayInMilliseconds, subscriptionIntervalInMilliseconds);
-
-            newClient.init(clientParams.toBuilder().clearBulletinBoardAddress().addBulletinBoardAddress(address).build());
-
-            subscriberClients.add(newClient);
-
-        }
-
-        subscriber = new ThreadedBulletinBoardSubscriber(subscriberClients, localClient);
-
-    }
 
     @Override
     public MessageID postMessage(BulletinBoardMessage msg) throws CommunicationException {
-        return null;
+        localClient.postMessage(msg);
+        return remoteClient.postMessage(msg);
     }
 
     @Override
     public float getRedundancy(MessageID id) {
-        return 0;
+        return remoteClient.getRedundancy(id);
     }
 
     @Override
     public List<BulletinBoardMessage> readMessages(MessageFilterList filterList) {
-        return null;
+        subscriber.subscribe(filterList, new SubscriptionStoreCallback());
+        return localClient.readMessages(filterList);
     }
 
     @Override
-    public SyncQuery generateSyncQuery(GenerateSyncQueryParams GenerateSyncQueryParams) throws CommunicationException {
+    public SyncQuery generateSyncQuery(GenerateSyncQueryParams generateSyncQueryParams) throws CommunicationException {
-        return null;
+        return localClient.generateSyncQuery(generateSyncQueryParams);
     }
 
     @Override
     public void close() {
-
+        localClient.close();
+        remoteClient.close();
     }
 
     @Override
     public void subscribe(MessageFilterList filterList, FutureCallback<List<BulletinBoardMessage>> callback) {
-
+        subscriber.subscribe(filterList, callback);
     }
 
     @Override
     public void subscribe(MessageFilterList filterList, long startEntry, FutureCallback<List<BulletinBoardMessage>> callback) {
+        subscriber.subscribe(filterList, startEntry, callback);
+    }
+
+    public int syncStatus(){
+        return 0;
+    }
+
+    public void reSync(){
 
     }
+
 }

bulletin-board-client/src/main/java/meerkat/bulletinboard/LocalBulletinBoardClient.java

@@ -22,14 +22,14 @@ import java.util.concurrent.TimeUnit;
 
 /**
  * Created by Arbel Deutsch Peled on 15-Mar-16.
- * This client is to be used mainly for testing.
+ * This client wraps a BulletinBoardServer in an asynchronous client.
- * It wraps a BulletinBoardServer in an asynchronous client.
+ * It is meant to be used as a local cache handler and for testing purposes.
  * This means the access to the server is direct (via method calls) instead of through a TCP connection.
  * The client implements both synchronous and asynchronous method calls, but calls to the server itself are performed synchronously.
  */
-public class LocalBulletinBoardClient implements SubscriptionAsyncBulletinBoardClient{
+public class LocalBulletinBoardClient implements DeletableSubscriptionBulletinBoardClient {
 
-    private final BulletinBoardServer server;
+    private final DeletableBulletinBoardServer server;
     private final ListeningScheduledExecutorService executorService;
     private final BatchDigest digest;
     private final int subsrciptionDelay;
@@ -40,7 +40,7 @@ public class LocalBulletinBoardClient implements SubscriptionAsyncBulletinBoardC
      * @param threadNum is the number of concurrent threads to allocate for the client
      * @param subscriptionDelay is the required delay between subscription calls in milliseconds
      */
-    public LocalBulletinBoardClient(BulletinBoardServer server, int threadNum, int subscriptionDelay) {
+    public LocalBulletinBoardClient(DeletableBulletinBoardServer server, int threadNum, int subscriptionDelay) {
         this.server = server;
         this.executorService = MoreExecutors.listeningDecorator(Executors.newScheduledThreadPool(threadNum));
         this.digest = new GenericBatchDigest(new SHA256Digest());
@@ -517,8 +517,30 @@ public class LocalBulletinBoardClient implements SubscriptionAsyncBulletinBoardC
     }
 
     @Override
-    public SyncQuery generateSyncQuery(GenerateSyncQueryParams GenerateSyncQueryParams) throws CommunicationException {
+    public SyncQuery generateSyncQuery(GenerateSyncQueryParams generateSyncQueryParams) throws CommunicationException {
-        return server.generateSyncQuery(GenerateSyncQueryParams);
+        return server.generateSyncQuery(generateSyncQueryParams);
+    }
+
+    @Override
+    public void deleteMessage(MessageID msgID, FutureCallback<Boolean> callback) {
+
+        try {
+            callback.onSuccess(server.deleteMessage(msgID).getValue());
+        } catch (CommunicationException e) {
+            callback.onFailure(e);
+        }
+
+    }
+
+    @Override
+    public void deleteMessage(long entryNum, FutureCallback<Boolean> callback) {
+
+        try {
+            callback.onSuccess(server.deleteMessage(entryNum).getValue());
+        } catch (CommunicationException e) {
+            callback.onFailure(e);
+        }
+
     }
 
     @Override

bulletin-board-client/src/main/java/meerkat/bulletinboard/SingleServerBulletinBoardClient.java

@@ -7,12 +7,10 @@ import com.google.common.util.concurrent.MoreExecutors;
 import com.google.protobuf.ByteString;
 import meerkat.bulletinboard.workers.singleserver.*;
 import meerkat.comm.CommunicationException;
-import meerkat.protobuf.BulletinBoardAPI;
 import meerkat.protobuf.BulletinBoardAPI.*;
 import meerkat.protobuf.Voting.BulletinBoardClientParams;
 import meerkat.util.BulletinBoardUtils;
 
-import javax.ws.rs.NotFoundException;
 import java.util.Arrays;
 import java.util.Iterator;
 import java.util.LinkedList;
@@ -30,7 +28,7 @@ import java.util.concurrent.atomic.AtomicInteger;
  * If the list of servers contains more than one server: the server actually used is the first one
  * The class further implements a delayed access to the server after a communication error occurs
  */
-public class SingleServerBulletinBoardClient extends SimpleBulletinBoardClient implements SubscriptionAsyncBulletinBoardClient {
+public class SingleServerBulletinBoardClient extends SimpleBulletinBoardClient implements SubscriptionBulletinBoardClient {
 
     private final int MAX_RETRIES = 11;
 

bulletin-board-client/src/main/java/meerkat/bulletinboard/ThreadedBulletinBoardSubscriber.java

@@ -8,7 +8,6 @@ import meerkat.util.BulletinBoardUtils;
 
 import static meerkat.protobuf.BulletinBoardAPI.FilterType.*;
 
-import java.sql.Time;
 import java.util.*;
 import java.util.concurrent.Semaphore;
 import java.util.concurrent.atomic.AtomicBoolean;
@@ -19,11 +18,11 @@ import java.util.concurrent.atomic.AtomicBoolean;
  */
 public class ThreadedBulletinBoardSubscriber implements BulletinBoardSubscriber {
 
-    protected final Collection<SubscriptionAsyncBulletinBoardClient> clients;
+    protected final Collection<SubscriptionBulletinBoardClient> clients;
     protected final BulletinBoardClient localClient;
 
-    protected Iterator<SubscriptionAsyncBulletinBoardClient> clientIterator;
+    protected Iterator<SubscriptionBulletinBoardClient> clientIterator;
-    protected SubscriptionAsyncBulletinBoardClient currentClient;
+    protected SubscriptionBulletinBoardClient currentClient;
 
     private long lastServerSwitchTime;
 
@@ -32,7 +31,7 @@ public class ThreadedBulletinBoardSubscriber implements BulletinBoardSubscriber
 
     private static final Float[] BREAKPOINTS = {0.5f, 0.75f, 0.9f, 0.95f, 0.99f, 0.999f};
 
-    public ThreadedBulletinBoardSubscriber(Collection<SubscriptionAsyncBulletinBoardClient> clients, BulletinBoardClient localClient) {
+    public ThreadedBulletinBoardSubscriber(Collection<SubscriptionBulletinBoardClient> clients, BulletinBoardClient localClient) {
 
         this.clients = clients;
         this.localClient = localClient;

bulletin-board-client/src/test/java/meerkat/bulletinboard/GenericSubscriptionClientTester.java

@@ -17,7 +17,6 @@ import java.util.*;
 import java.util.concurrent.Semaphore;
 
 import static org.hamcrest.CoreMatchers.is;
-import static org.hamcrest.CoreMatchers.startsWith;
 import static org.junit.Assert.assertThat;
 import static org.junit.Assert.fail;
 
@@ -38,7 +37,7 @@ public class GenericSubscriptionClientTester {
     private static String CERT1_PEM_EXAMPLE = "/certs/enduser-certs/user1.crt";
     private static String CERT3_PEM_EXAMPLE = "/certs/enduser-certs/user3.crt";
 
-    private SubscriptionAsyncBulletinBoardClient bulletinBoardClient;
+    private SubscriptionBulletinBoardClient bulletinBoardClient;
 
     private Random random;
     private BulletinBoardMessageGenerator generator;
@@ -46,7 +45,7 @@ public class GenericSubscriptionClientTester {
     private Semaphore jobSemaphore;
     private Vector<Throwable> thrown;
 
-    public GenericSubscriptionClientTester(SubscriptionAsyncBulletinBoardClient bulletinBoardClient){
+    public GenericSubscriptionClientTester(SubscriptionBulletinBoardClient bulletinBoardClient){
 
         this.bulletinBoardClient = bulletinBoardClient;
 

bulletin-board-client/src/test/java/meerkat/bulletinboard/LocalBulletinBoardClientTest.java

@@ -48,7 +48,7 @@ public class LocalBulletinBoardClientTest {
             throw new CommunicationException(e.getCause() + " " + e.getMessage());
         }
 
-        BulletinBoardServer server = new BulletinBoardSQLServer(queryProvider);
+        DeletableBulletinBoardServer server = new BulletinBoardSQLServer(queryProvider);
         server.init(DB_NAME);
 
         LocalBulletinBoardClient client = new LocalBulletinBoardClient(server, THREAD_NUM, SUBSRCIPTION_DELAY);

bulletin-board-server/src/main/java/meerkat/bulletinboard/sqlserver/BulletinBoardSQLServer.java

@@ -6,6 +6,7 @@ import java.util.*;
 import com.google.protobuf.*;
 
 import com.google.protobuf.Timestamp;
+import com.sun.org.apache.xpath.internal.operations.Bool;
 import meerkat.bulletinboard.*;
 import meerkat.bulletinboard.sqlserver.mappers.*;
 import static meerkat.bulletinboard.BulletinBoardConstants.*;
@@ -16,6 +17,7 @@ import meerkat.comm.MessageOutputStream;
 import meerkat.crypto.concrete.ECDSASignature;
 import meerkat.crypto.concrete.SHA256Digest;
 
+import meerkat.protobuf.BulletinBoardAPI;
 import meerkat.protobuf.BulletinBoardAPI.*;
 import meerkat.protobuf.Crypto.Signature;
 import meerkat.protobuf.Crypto.SignatureVerificationKey;
@@ -38,7 +40,7 @@ import org.springframework.jdbc.support.KeyHolder;
 /**
  * This is a generic SQL implementation of the BulletinBoardServer API.
  */
-public class BulletinBoardSQLServer implements BulletinBoardServer{
+public class BulletinBoardSQLServer implements DeletableBulletinBoardServer{
 
 	/**
 	 * This interface provides the required implementation-specific data to enable an access to an actual SQL server.
@@ -67,6 +69,16 @@ public class BulletinBoardSQLServer implements BulletinBoardServer{
 					new int[] {Types.BLOB, Types.TIMESTAMP, Types.BLOB}
 			),
 
+			DELETE_MSG_BY_ENTRY(
+					new String[] {"EntryNum"},
+					new int[] {Types.INTEGER}
+			),
+
+			DELETE_MSG_BY_ID(
+					new String[] {"MsgId"},
+					new int[] {Types.BLOB}
+			),
+
 			INSERT_NEW_TAG(
 					new String[] {"Tag"},
 					new int[] {Types.VARCHAR}
@@ -529,6 +541,38 @@ public class BulletinBoardSQLServer implements BulletinBoardServer{
 		return postMessage(msg, true);	// Perform a post and check the signature for authenticity
 	}
 
+	@Override
+	public BoolMsg deleteMessage(MessageID msgID) throws CommunicationException {
+
+		String sql = sqlQueryProvider.getSQLString(QueryType.DELETE_MSG_BY_ID);
+		Map namedParameters = new HashMap();
+
+		namedParameters.put(QueryType.DELETE_MSG_BY_ID.getParamName(0),msgID);
+
+		int affectedRows = jdbcTemplate.update(sql, namedParameters);
+
+		//TODO: Log
+
+		return BoolMsg.newBuilder().setValue(affectedRows > 0).build();
+
+	}
+
+	@Override
+	public BoolMsg deleteMessage(long entryNum) throws CommunicationException {
+
+		String sql = sqlQueryProvider.getSQLString(QueryType.DELETE_MSG_BY_ENTRY);
+		Map namedParameters = new HashMap();
+
+		namedParameters.put(QueryType.DELETE_MSG_BY_ENTRY.getParamName(0),entryNum);
+
+		int affectedRows = jdbcTemplate.update(sql, namedParameters);
+
+		//TODO: Log
+
+		return BoolMsg.newBuilder().setValue(affectedRows > 0).build();
+
+	}
+
 
 	/**
 	 * This is a container class for and SQL string builder and a MapSqlParameterSource to be used with it

bulletin-board-server/src/main/java/meerkat/bulletinboard/sqlserver/H2QueryProvider.java

@@ -30,19 +30,28 @@ public class H2QueryProvider implements BulletinBoardSQLServer.SQLQueryProvider
 
         switch(queryType) {
             case ADD_SIGNATURE:
-                return "INSERT INTO SignatureTable (EntryNum, SignerId, Signature)"
+                return MessageFormat.format(
-                        + " SELECT DISTINCT :EntryNum AS Entry, :SignerId AS Id, :Signature AS Sig FROM UtilityTable AS Temp"
+                        "INSERT INTO SignatureTable (EntryNum, SignerId, Signature)"
-                        + " WHERE NOT EXISTS"
+                            + " SELECT DISTINCT :{0} AS Entry, :{1} AS Id, :{2} AS Sig FROM UtilityTable AS Temp"
-                        + " (SELECT 1 FROM SignatureTable AS SubTable WHERE SubTable.SignerId = :SignerId AND SubTable.EntryNum = :EntryNum)";
+                            + " WHERE NOT EXISTS"
+                            + " (SELECT 1 FROM SignatureTable AS SubTable WHERE SubTable.EntryNum = :{0} AND SubTable.SignerId = :{1})",
+                        QueryType.ADD_SIGNATURE.getParamName(0),
+                        QueryType.ADD_SIGNATURE.getParamName(1),
+                        QueryType.ADD_SIGNATURE.getParamName(2));
 
             case CONNECT_TAG:
-                return "INSERT INTO MsgTagTable (TagId, EntryNum)"
+                return MessageFormat.format(
-                        + " SELECT DISTINCT TagTable.TagId, :EntryNum AS NewEntry FROM TagTable WHERE Tag = :Tag"
+                        "INSERT INTO MsgTagTable (TagId, EntryNum)"
-                        + " AND NOT EXISTS (SELECT 1 FROM MsgTagTable AS SubTable WHERE SubTable.TagId = TagTable.TagId"
+                            + " SELECT DISTINCT TagTable.TagId, :{0} AS NewEntry FROM TagTable WHERE Tag = :{1}"
-                            + " AND SubTable.EntryNum = :EntryNum)";
+                            + " AND NOT EXISTS (SELECT 1 FROM MsgTagTable AS SubTable WHERE SubTable.TagId = TagTable.TagId"
+                            + " AND SubTable.EntryNum = :{0})",
+                        QueryType.CONNECT_TAG.getParamName(0),
+                        QueryType.CONNECT_TAG.getParamName(1));
 
             case FIND_MSG_ID:
-                return "SELECT EntryNum From MsgTable WHERE MsgId = :MsgId";
+                return MessageFormat.format(
+                        "SELECT EntryNum From MsgTable WHERE MsgId = :{0}",
+                        QueryType.FIND_MSG_ID.getParamName(0));
 
             case FIND_TAG_ID:
                 return MessageFormat.format(
@@ -59,14 +68,32 @@ public class H2QueryProvider implements BulletinBoardSQLServer.SQLQueryProvider
                 return "SELECT MsgTable.EntryNum, MsgTable.MsgId, MsgTable.ExactTime FROM MsgTable";
 
             case GET_SIGNATURES:
-                return "SELECT Signature FROM SignatureTable WHERE EntryNum = :EntryNum";
+                return MessageFormat.format(
+                        "SELECT Signature FROM SignatureTable WHERE EntryNum = :{0}",
+                        QueryType.GET_SIGNATURES.getParamName(0));
 
             case INSERT_MSG:
-                return "INSERT INTO MsgTable (MsgId, Msg, ExactTime) VALUES(:MsgId,:Msg,:TimeStamp)";
+                return MessageFormat.format(
+                        "INSERT INTO MsgTable (MsgId, ExactTime, Msg) VALUES(:{0}, :{1}, :{2})",
+                        QueryType.INSERT_MSG.getParamName(0),
+                        QueryType.INSERT_MSG.getParamName(1),
+                        QueryType.INSERT_MSG.getParamName(2));
+
+            case DELETE_MSG_BY_ENTRY:
+                return MessageFormat.format(
+                        "DELETE FROM MsgTable WHERE EntryNum = :{0}",
+                        QueryType.DELETE_MSG_BY_ENTRY.getParamName(0));
+
+            case DELETE_MSG_BY_ID:
+                return MessageFormat.format(
+                        "DELETE FROM MsgTable WHERE MsgId = :{0}",
+                        QueryType.DELETE_MSG_BY_ID.getParamName(0));
 
             case INSERT_NEW_TAG:
-                return "INSERT INTO TagTable(Tag) SELECT DISTINCT :Tag AS NewTag FROM UtilityTable WHERE"
+                return MessageFormat.format(
-                        + " NOT EXISTS (SELECT 1 FROM TagTable AS SubTable WHERE SubTable.Tag = :Tag)";
+                        "INSERT INTO TagTable(Tag) SELECT DISTINCT :Tag AS NewTag FROM UtilityTable WHERE"
+                            + " NOT EXISTS (SELECT 1 FROM TagTable AS SubTable WHERE SubTable.Tag = :{0})",
+                        QueryType.INSERT_NEW_TAG.getParamName(0));
 
             case GET_LAST_MESSAGE_ENTRY:
                 return "SELECT MAX(MsgTable.EntryNum) FROM MsgTable";

bulletin-board-server/src/main/java/meerkat/bulletinboard/sqlserver/MySQLQueryProvider.java

@@ -1,7 +1,5 @@
 package meerkat.bulletinboard.sqlserver;
 
-import com.mysql.jdbc.jdbc2.optional.MysqlDataSource;
-import meerkat.bulletinboard.BulletinBoardConstants;
 import meerkat.bulletinboard.sqlserver.BulletinBoardSQLServer.SQLQueryProvider;
 import meerkat.protobuf.BulletinBoardAPI.FilterType;
 import org.apache.commons.dbcp2.BasicDataSource;
@@ -81,6 +79,16 @@ public class MySQLQueryProvider implements SQLQueryProvider {
                         QueryType.INSERT_MSG.getParamName(1),
                         QueryType.INSERT_MSG.getParamName(2));
 
+            case DELETE_MSG_BY_ENTRY:
+                return MessageFormat.format(
+                        "DELETE IGNORE FROM MsgTable WHERE EntryNum = :{0}",
+                        QueryType.DELETE_MSG_BY_ENTRY.getParamName(0));
+
+            case DELETE_MSG_BY_ID:
+                return MessageFormat.format(
+                        "DELETE IGNORE FROM MsgTable WHERE MsgId = :{0}",
+                        QueryType.DELETE_MSG_BY_ID.getParamName(0));
+
             case INSERT_NEW_TAG:
                 return MessageFormat.format(
                         "INSERT IGNORE INTO TagTable(Tag) VALUES (:{0})",

meerkat-common/src/main/java/meerkat/bulletinboard/BulletinBoardClient.java

@@ -47,12 +47,12 @@ public interface BulletinBoardClient {
     /**
      * Create a SyncQuery to test against that corresponds with the current server state for a specific filter list
      * Should only be called on instances for which the actual server contacted is known (i.e. there is only one server)
-     * @param GenerateSyncQueryParams defines the required information needed to generate the query
+     * @param generateSyncQueryParams defines the required information needed to generate the query
      *                    These are represented as fractions of the total number of relevant messages
      * @return The generated SyncQuery
      * @throws CommunicationException when no DB can be contacted
      */
-    SyncQuery generateSyncQuery(GenerateSyncQueryParams GenerateSyncQueryParams) throws CommunicationException;
+    SyncQuery generateSyncQuery(GenerateSyncQueryParams generateSyncQueryParams) throws CommunicationException;
 
     /**
      * Closes all connections, if any.

meerkat-common/src/main/java/meerkat/bulletinboard/BulletinBoardMessageDeleter.java

@@ -0,0 +1,30 @@
+package meerkat.bulletinboard;
+
+import com.google.common.util.concurrent.FutureCallback;
+import meerkat.comm.CommunicationException;
+import meerkat.protobuf.BulletinBoardAPI.*;
+
+/**
+ * Created by Arbel Deutsch Peled on 13-Apr-16.
+ * This interface is meant to extend a BulletinBoardClient interface/class
+ * It provides it with the ability to delete messages from the Server
+ * This assumes the Server implements the  {@link DeletableBulletinBoardServer}
+ */
+public interface BulletinBoardMessageDeleter {
+
+    /**
+     * Deletes a message from a Bulletin Board Server
+     * @param msgID is the ID of the message to delete
+     * @param callback handles the result of the operation
+     */
+    public void deleteMessage(MessageID msgID, FutureCallback<Boolean> callback);
+
+    /**
+     * Deletes a message from the Bulletin Board
+     * Logs this action
+     * @param entryNum is the serial entry number of the message to delete
+     * @param callback handles the result of the operation
+     */
+    public void deleteMessage(long entryNum, FutureCallback<Boolean> callback);
+
+}

meerkat-common/src/main/java/meerkat/bulletinboard/DeletableBulletinBoardServer.java

@@ -0,0 +1,29 @@
+package meerkat.bulletinboard;
+
+import meerkat.comm.CommunicationException;
+import meerkat.protobuf.BulletinBoardAPI.*;
+
+/**
+ * Created by Arbel Deutsch Peled on 13-Apr-16.
+ */
+public interface DeletableBulletinBoardServer extends BulletinBoardServer {
+
+    /**
+     * Deletes a message from the Bulletin Board
+     * Logs this action
+     * @param msgID is the ID of the message to delete
+     * @return a BoolMsg containing the value TRUE if a message was deleted, FALSE if the message does not exist
+     * @throws CommunicationException in case of an error
+     */
+    public BoolMsg deleteMessage(MessageID msgID) throws CommunicationException;
+
+    /**
+     * Deletes a message from the Bulletin Board
+     * Logs this action
+     * @param entryNum is the serial entry number of the message to delete
+     * @return a BoolMsg containing the value TRUE if a message was deleted, FALSE if the message does not exist
+     * @throws CommunicationException in case of an error
+     */
+    public BoolMsg deleteMessage(long entryNum) throws CommunicationException;
+
+}

meerkat-common/src/main/java/meerkat/bulletinboard/DeletableSubscriptionBulletinBoardClient.java

@@ -0,0 +1,7 @@
+package meerkat.bulletinboard;
+
+/**
+ * Created by Arbel Deutsch Peled on 13-Apr-16.
+ */
+public interface DeletableSubscriptionBulletinBoardClient extends SubscriptionBulletinBoardClient, BulletinBoardMessageDeleter {
+}

meerkat-common/src/main/java/meerkat/bulletinboard/SubscriptionAsyncBulletinBoardClient.java

@@ -1,7 +0,0 @@
-package meerkat.bulletinboard;
-
-/**
- * Created by Arbel Deutsch Peled on 03-Mar-16.
- */
-public interface SubscriptionAsyncBulletinBoardClient extends AsyncBulletinBoardClient, BulletinBoardSubscriber {
-}

meerkat-common/src/main/java/meerkat/bulletinboard/SubscriptionBulletinBoardClient.java

@@ -0,0 +1,7 @@
+package meerkat.bulletinboard;
+
+/**
+ * Created by Arbel Deutsch Peled on 03-Mar-16.
+ */
+public interface SubscriptionBulletinBoardClient extends AsyncBulletinBoardClient, BulletinBoardSubscriber {
+}